package com.potato.study.leetcode.p0240;

/**
 * 
 * @author liuzhao11
 * 
     *     240. Search a 2D Matrix II
 * 
 *Write an efficient algorithm that searches for a value in an m x n matrix. This matrix has the following properties:

Integers in each row are sorted in ascending from left to right.
Integers in each column are sorted in ascending from top to bottom.
Example:

Consider the following matrix:

[
[1,   4,  7, 11, 15],
[2,   5,  8, 12, 19],
[3,   6,  9, 16, 22],
[10, 13, 14, 17, 24],
[18, 21, 23, 26, 30]
]
Given target = 5, return true.

Given target = 20, return false.

 * 题目含义：
 *     有序矩阵中找数字
 * 思路：
 *     从左下角开始
 *
 */
public class Solution {

    public boolean searchMatrix(int[][] matrix, int target) {
        if (null == matrix || matrix.length == 0 || matrix[0] == null || matrix[0].length == 0) {
            return false;
        }
        int x = matrix.length - 1;
        int y = 0;
        while (x >= 0 && y < matrix[0].length) {
            if (target == matrix[x][y]) {
                return true;
            } else if (target > matrix[x][y]) {
                y++;
            } else {
                x--;
            }
        }
        return false;
    }
    public static void main(String[] args) {
    	Solution solution = new Solution();
    }
}
